1. Field of the Invention
The present invention concerns a system and technique for deploying fiber optic cabling for users in multi-dwelling unit (MDU) premises and commercial office buildings.
2. Discussion of the Known Art
The deployment of fiber optic networks at multi-dwelling units (MDUs) and other subscriber premises, requires the use of so-called cable drop boxes which are constructed for mounting on walls or other structures at the premises. Current industry practice calls for the boxes to have a cable entry port at the left side of the box to receive a fiber optic cable originating from the network provider, and one or more ports at the right side of the box through which a number of fibers associated with individual subscribers at the premises are received to be connected with corresponding fibers in the provider cable. See, for example, Corning Cable Systems, Wall-Mountable Connector Housings, at <www.corningcablesystems.com>, and ADC Telecommunications, Indoor Fiber Distribution Terminals—Customer Premises Equipment (CPE), at <www.adc.com/ productsandservices/>. See also, 2007 Multilink Catalog, vol. 24, at pages 87-94, disclosing a family of wall mountable fiber optic cable enclosures available from Multilink, Inc., of Elyria, Ohio, USA.
Installation of the known cable drop boxes by a single worker at a subscriber premises can be difficult and time consuming, however. Further, the known boxes are dimensioned to accommodate older types of fiber optic cables that can not tolerate bend diameters of less than three inches (76.2 mm) without impairing cable performance. Accordingly, the currently available drop boxes are relatively large, and are not suitable for widespread deployment of fiber optic networks at multi-dwelling units or other buildings without significant expenditures of time and labor.
Moreover, in current outdoor fiber-to-the-home (FTTH) deployments, fiber-optic network service is brought to residences through an array of optical fiber distribution and drop cables. For example, the head end of a distribution cable is terminated at a splitter/splice cabinet the field, where the distribution cable connects with a trunk cable originating from a central office. The distribution cable is then run aerially or below grade through the residential neighborhood to be served by the network. Drop cables that service individual residences are connected with the distribution cable through terminations at splice closures or connections at network terminals such as, e.g., a so-called FlexNAP terminal available from Corning. When a fiber in the distribution cable is accessed mid-span, it is coupled to either a “tether” leading to a network terminal, or directly to a drop cable. The portion of that individual fiber that remains in the distribution cable is then left unused and becomes “dead”, however. Accordingly, when multiple midspan access points are required for drops, half of the fiber in the distribution cable may be left unused or is wasted.
Another problem arises when bringing a fiber optic network distribution system to a multi-dwelling residence or office building. For example, the Corning FlexNAP system requires factory installation of the mentioned “tethers” from the distribution cable, at various points along the length of the cable. In an outdoor aerial network, access to the tethers is fairly simple, since the tethers may be accessed at any point using a “cherry picker” or similar lift apparatus. In a residential or commercial office building, however, the distribution cable is typically in the form of a riser cable that is routed inside a vertical shaft or conduit between floors of the building. The size of the riser shafts and the means available for accessing them typically vary from building to building. Thus, it may be difficult if not impossible to access the tethers on a fiber optic distribution cable once the cable is placed in the riser shaft of an existing building.